1. Field of the Invention
The present invention relates to a magnet wheel for an electric motor, having a shaft and a disk made of a plastic containing magnetic particles. The disk is arranged on a support hub, and the support hub is pressed with the shaft.
2. Related Art
Such magnet wheels are used in brushless DC motors as part of position sensors and are therefore known. The disk of the magnet wheel is produced by injection molding a plastic containing iron particles onto the support hub. The support hub is a closed ring made of a suitable material, such as steel or brass. Then, the support hub, with the disk injection-molded on, is pressed onto the shaft. The disadvantage with this configuration is that, owing to manufacturing tolerances of the shaft, considerable stresses sometimes occur in the support huh when the support hub is pressed on, and these stresses reduce the life of the magnet wheel. In particularly severe cases, there is the risk of the magnet wheel being impaired, which may result in malfunctions in the position sensor.